I’m grateful to Dorothy Hoskins because she brought to my attention that when an InDesign document uses nested styles, the resulting styling does not get exported to RTF by TextExporter.
Further investigation showed that this is a limitation of the built-in InDesign RTF export.
To work around the issue, we’ve released version 3.2 of TextExporter – you can download it here:
https://www.rorohiko.com/TextExporter
This version has an option ‘Emulate Bullets & Nested Styles’. When you enable this option, you’ll find that the styling resulting from nested styles will make it through into the exported RTF file.
(Yes, Virginia, there is a built-in RTF export in InDesign. It only works on a story-by-story basis, and many people miss it because the option only appears in the export format popup menu when you have an active text cursor or text selection in InDesign. Try it: create a text frame, fill with placeholder text, plunk your text cursor somewhere in the text. Now File – Export…, and look in the popup menu. Tadaa!)